A conventional aircraft wing comprises a main wing element with a spar; a high lift device (such as a slat or Krueger flap) which is movably mounted to the main wing element; and an actuation mechanism which moves the high lift device between a retracted position and an extended position in which the high lift device increases the camber of the wing. A known mechanisms comprises a drive shaft which runs span-wise along the wing, and an actuator shaft which is positioned forward of the drive shaft and also runs span-wise along the wing. Power is transmitted from the drive shaft to the actuator shaft via two bevel gears, a down-drive shaft between the bevel gears, and a gear box extending in line with the actuator shaft. A problem with such an actuator mechanism is that the gearbox takes up valuable space.